         new-col-ids (keys first-result)]
 
     new-col-ids))
-
-(defn lift->vector [x]
-  (if (sequential? x) x [x]))
 
 (defn add-columns
   ([dataset hash]

  [dataset n]
  (tabc/pass-rows dataset (partial take n)))

(defn derive-column
  "Adds a new column to the end of the row which is derived from
column with position col-n.  f should just return the cells value.

   (derive-column dataset new-column-name from-cols identity))
  ;; todo support multiple columns/arguments to f.
  ([dataset new-column-name from-cols f]
     (inc/add-derived-column new-column-name (lift->vector from-cols) f dataset)))

(defn- resolve-keys [headers hash]
  (map-keys #(resolve-col-id % headers nil) hash))
